Electrolyte for lithium secondary battery and lithium secondary battery including the same

Patent metadata

Field	Value
Publication number	US-9590266-B2
Application number	US-201213546697-A
Country	US
Kind code	B2
Filing date	Jul 11, 2012
Priority date	Sep 22, 2011
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

An electrolyte for a lithium secondary battery, the electrolyte including a lithium salt, a non-aqueous organic solvent, and a polar additive based on a substituted hetero-bicyclic compound. Oxidation of the electrolyte is prevented by formation of a polar thin film on a surface portion of the positive electrode, which facilitates transfer of lithium ions. The lithium secondary batteries using the electrolyte have excellent high temperature life characteristics and high temperature conservation characteristics.

First claim

What is claimed is:

1. An electrolyte for a lithium secondary battery, the electrolyte comprising a lithium salt, a non-aqueous organic solvent, and an additive represented by Formula 1 below:

wherein A 1 to A 9 are each, independently,

with the proviso that A 1 to A 9 include at least one of

CY1 is a C3-C6 aromatic ring, and CY2 is a C3-C5 aromatic or non-aromatic ring;
B 1 and B 2 are each independently a single bond,

 or a C1-C5 alkylene group;
and R 1 and R 2 are each independently hydrogen, a halogen group, a cyano group, a hydroxyl group, —C(═O)R a , —C(═O)OR a , —OCO(OR a ), —C═N(R a ), —SR a , —S(═O)R a , —S(═O) 2 R a , —PR a , a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1 -C20 alkoxy group, a substituted or unsubstituted C2-C20 alkenyl group, a substituted or unsubstituted C2-C20 alkynyl group, a C2-C20 alkylene oxide group, a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C6-C30 aryloxy group, a substituted or unsubstituted C6-C30 heteroaryl group, or combinations thereof, wherein R a is a C1-C10 alkyl group, or a C6-C20 aryl group, with the proviso that at least one of R 1 and R 2 includes a polar functional group selected from the group consisting of a halogen group, —C(═O)R a , —C(═O)OR a , —OCO(OR a ), C═N(R a ), —SR a , —PR a , a substituted or unsubstituted C1-C20 alkoxy group, a C2-C20 alkylene oxide group, a substituted or unsubstituted C6-C30 aryloxy group, and a substituted or unsubstituted C6-C30 heteroaryl group, and with the proviso that at least one of R 1 is SR a , wherein R a is a C1-C10 alkyl group, or a C6-C20 aryl group, wherein a film that is partially or fully derived from the additive in the electrolyte is formed on a surface of a positive electrode in the lithium secondary battery.

2. The electrolyte of claim 1 , wherein the additive is represented by Formula 2 below:

wherein A 1 and A 2 are each, independently,

with the proviso that A 1 and A 2 include at least one of

B 3 and B 4 are each independently a single bond,

 or a C1-C5alkylene group; and
R′ 1 , R″ 1 , R″ 2 , R″ 3 , and R″ 4 are each independently hydrogen, a halogen group, a hydroxyl group, a cyano group, —C(═O)R a , —C(═O)OR a , —OCO(OR a ), —C═N(R a ), —SR a , —S(═O)R a , —S(═O) 2 R a , —PR a , a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1-C20 alkoxy group, a substituted or unsubstituted C2-C20alkenyl group, a substituted or unsubstituted C2-C20 alkynyl group, a C2-C20alkylene oxide group, a substituted or unsubstituted C3-C30 cycloalkyl group, a substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C6-C30aryloxy group, a substituted or unsubstituted C6-C30 heteroaryl group, or a combination thereof, wherein R a is a C1-C10 alkyl group, or a C6-C20 aryl group, with the proviso that at least one of R′ 1 , R″ 1 , R″ 2 , R″ 3 , and R″ 4 includes a polar functional group selected from the group consisting of a halogen group, —C(═O)R a , —C(═O)OR a , —OCO(OR a ), C═N(R a ), —SR a , —PR a , a substituted or unsubstituted C1-C20 alkoxy group, a C2-C20 alkylene oxide group, a substituted or unsubstituted C6-C30 aryloxy group, and a substituted or unsubstituted C6-C30 heteroaryl group, and with the proviso that at least one of R′ 2 , R″ 1 , R″ 2 , R″ 3 , and R″ 4 is —SR a , wherein R a is a C1-C10 alkyl group, or a C6C20 aryl group.

3. The electrolyte of claim 2 , wherein the additive is at least one compound selected from the group consisting of

4. The electrolyte of claim 3 , wherein the additive is at least one compound selected from the group consisting of

5. The electrolyte of claim 4 , wherein the additive is at least one compound selected from the group consisting of

6. The electrolyte of claim 1 , wherein the amount of the additive is in a range of about 0.005 to about 10 wt % based on the total weight of the electrolyte.

7. The electrolyte of claim 6 , wherein the amount of the additive is in a range of about 0.01 to about 5 wt % based on the total weight of the electrolyte.

8. The electrolyte of claim 1 , wherein the lithium salt is at least one compound selected from LiPF 6 , LiBF 4 , LiSbF 6 , LiAsF 6 , LiCF 3 SO 3 , Li(CF 3 SO 2 ) 3 C, Li(CF 3 SO 2 ) 2 N, LiC 4 F 9 SO 3 , LiClO 4 , LiAlO 4 , LiAlCl 4 , LiBPh 4 , LiN(C x F 2x+1 SO 2 )(C x F 2y+1 SO 2 ) where x and y are natural numbers, LiCl, LiI, lithium bisoxalate borate (LIBOB), and combinations thereof.

9. The electrolyte of claim 1 , wherein the non-aqueous organic solvent is a carbonate-based solvent, an ester-based solvent, an ether-based solvent, a ketone-based solvent, an alcohol-based solvent, a non-protonic solvent, or combinations thereof.

10. A lithium secondary battery comprising:
a positive electrode comprising a positive active material into or from which lithium ions are intercalated or deintercalated;
a negative electrode comprising a negative active material into or from which lithium ions are intercalated or deintercalated; and
an electrolyte interposed between the positive electrode and the negative electrode,
wherein the electrolyte comprises a lithium salt, a non-aqueous organic solvent, and an additive represented by Formula 1 below:

wherein A 1 to A 9 are each, independently,

with the proviso that A 1 to A 9 include at least one of

CY1 is a C3-C6 aromatic ring, and CY2 is a C3-C5 aromatic or non-aromatic ring;
B 1 and B 2 are each independently a single bond,

 or a C1-C5 alkylene group; and
R 1 and R 2 are each independently hydrogen, a halogen group, a cyano group, a hydroxyl group, —C(═O)R a , —C(═O)OR a , —OCO(OR a ), —C═N(R a ), —SR a , —S(═O)R a , —S(═O) 2 R a , —PR a , a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C1-C20alkoxy group, a substituted or unsubstituted C2-C20 alkenyl group, a substituted or unsubstituted C2-C20 alkynyl group, a C2-C20 alkylene oxide group, a substituted or unsubstituted C3-C30 cycloalkyl group, a subs

Assignees

• Kang Yoon-Sok
• Park Min-Sik
• Mun Jun-Young
• Park Jin-Hwan
• Lee Dong-Joon
• Samsung Electronics Co Ltd

Inventors

• Kang Yoon-Sok
• Park Min-Sik
• Mun Jun-Young
• Park Jin-Hwan
• Lee Dong-Joon

Classifications

• H01M10/0569

  characterised by the solvents · CPC title

• Y02E60/122

  Cross-Sectional Technologies · mapped topic

• Y02T10/7011

  Cross-Sectional Technologies · mapped topic

• H01M10/0525 Primary

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M10/0567 Primary

  characterised by the additives · CPC title